The section of Pulmonary Pathology, together with the Cytopathology Section, Hematopathology Section, Postmortem Section, Surgical Pathology Section, and Ultrastructural Pathology Section provide complete service in anatomic pathology for the Clinical Center patients and collaborate with the research staff of all institutes in those investigations which involve the use and study of human pathological material. The pulmonary section provides diagnostic services for several pulmonary groups at the NIH including the NIAID (Dr. Fauci) for vasculitis, the NHLBI, Pulmonary Branch (Dr. Crystal) for interstitial lung disease, Critical Care (Dr. Masur) for lung disease in immunocompromised patients; and the NCI, Surgery Branch (Dr. Pass) for lung cancer and malignant mesothelioma protocols. The pathology for all interstitial lung disease patients with lung biopsies is presented at Dr. Crystal's weekly, Friday noon conference. Surgical and autopsy lung specimens are reviewed on a daily basis for these various pulmonary groups. The pulmonary material is being utilized for research purposes to study lung cancer, malignant mesothelioma, and nonneoplastic interstitial lung disease. Electron microscopic and immunohistochemical techniques are being utilized to study these diseases. A prospective collaborative project has been undertaken in conjunction with Dr. Lance A. Liotta, Dr. Curtis C. Harris, and the lung cancer group at Mayo Clinic to investigate the molecular biology of lung cancer. In addition, a collaborative working relationship has been set up with the Pulmonary and Mediastinal Branch at the Armed Forces Institute of Pathology. This has allowed study of a wide variety of rare and unusual lung diseases including neuroendocrine tumors of the lung, pulmonary epithelioid hemangioendotheliomas, sclerosing hemangiomas, primitive neuroectodermal tumors presenting in the lung, and sarcomatoid carcinomas of the lung.